The invention relates to a method and apparatus for controlling the operation of an internal combustion engine so as to provide maximum power or minimum fuel consumption for the prevailing operational conditions. This optimization procedure is obtained by causing fluctuations of engine variables, for example the fuel quantity, the ignition angle, the air quantity or the like, and by sensing the resulting relative changes in the operation of the engine, for example in the crankshaft rotation. The center of the fluctuations of the engine variable is then adjusted in dependence on a comparison process.
A process and apparatus of the general type described above are known in which a mechanism for an automatic control of the internal combustion engine changes an engine variable continuously and relatively slowly within narrow limits. In this apparatus, an accelerometer is connected to the crankshaft of the engine and measures positive and negative accelerations. The signals from the accelerometer and the signals from the device causing a slow change in the engine variable are fed to a servo motor which changes the engine variable to correspond to the received signals.
It is a disadvantage of the above-described known method that it is very difficult to distinguish the forced modulation of the engine variable from the total positive or negative acceleration as measured by the accelerometer since, in normal operation, an internal combustion engine is nearly always subject to accelerations, so that the particular engine variables considered are almost continuously subjected to changes, for example by the operator himself, by braking, application of the gas pedal and the like. In addition, the known control method is not sufficiently rapid.